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<h1 class="title">linenode.cpp 示例文件</h1>
<span class="subtitle">scenegraph/graph/linenode.cpp</span>
<!-- $$$scenegraph/graph/linenode.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2017 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/</span>

  <span class="preprocessor">#include &quot;linenode.h&quot;</span>

  <span class="preprocessor">#include &lt;QtGui/QColor&gt;</span>

  <span class="preprocessor">#include &lt;QtQuick/QSGSimpleMaterial&gt;</span>

  <span class="keyword">struct</span> LineMaterial
  {
      <span class="type"><a href="../qtgui/qcolor.html">QColor</a></span> color;
      <span class="type">float</span> spread;
      <span class="type">float</span> size;
  };

  <span class="keyword">class</span> LineShader : <span class="keyword">public</span> <span class="type"><a href="qsgsimplematerialshader.html">QSGSimpleMaterialShader</a></span><span class="operator">&lt;</span>LineMaterial<span class="operator">&gt;</span>
  {
      QSG_DECLARE_SIMPLE_SHADER(LineShader<span class="operator">,</span> LineMaterial)

  <span class="keyword">public</span>:
      LineShader() {
          setShaderSourceFile(<span class="type"><a href="../qtgui/qopenglshader.html">QOpenGLShader</a></span><span class="operator">::</span>Vertex<span class="operator">,</span> <span class="string">&quot;:/scenegraph/graph/shaders/line.vsh&quot;</span>);
          setShaderSourceFile(<span class="type"><a href="../qtgui/qopenglshader.html">QOpenGLShader</a></span><span class="operator">::</span>Fragment<span class="operator">,</span> <span class="string">&quot;:/scenegraph/graph/shaders/line.fsh&quot;</span>);
      }

      <span class="type"><a href="../qtcore/qlist.html">QList</a></span><span class="operator">&lt;</span><span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span><span class="operator">&gt;</span> attributes() <span class="keyword">const</span> override {  <span class="keyword">return</span> <span class="type"><a href="../qtcore/qlist.html">QList</a></span><span class="operator">&lt;</span><span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span><span class="operator">&gt;</span>() <span class="operator">&lt;</span><span class="operator">&lt;</span> <span class="string">&quot;pos&quot;</span> <span class="operator">&lt;</span><span class="operator">&lt;</span> <span class="string">&quot;t&quot;</span>; }

      <span class="type">void</span> updateState(<span class="keyword">const</span> LineMaterial <span class="operator">*</span>m<span class="operator">,</span> <span class="keyword">const</span> LineMaterial <span class="operator">*</span>) override {
          program()<span class="operator">-</span><span class="operator">&gt;</span>setUniformValue(id_color<span class="operator">,</span> m<span class="operator">-</span><span class="operator">&gt;</span>color);
          program()<span class="operator">-</span><span class="operator">&gt;</span>setUniformValue(id_spread<span class="operator">,</span> m<span class="operator">-</span><span class="operator">&gt;</span>spread);
          program()<span class="operator">-</span><span class="operator">&gt;</span>setUniformValue(id_size<span class="operator">,</span> m<span class="operator">-</span><span class="operator">&gt;</span>size);
      }

      <span class="type">void</span> resolveUniforms() override {
          id_spread <span class="operator">=</span> program()<span class="operator">-</span><span class="operator">&gt;</span>uniformLocation(<span class="string">&quot;spread&quot;</span>);
          id_size <span class="operator">=</span> program()<span class="operator">-</span><span class="operator">&gt;</span>uniformLocation(<span class="string">&quot;size&quot;</span>);
          id_color <span class="operator">=</span> program()<span class="operator">-</span><span class="operator">&gt;</span>uniformLocation(<span class="string">&quot;color&quot;</span>);
      }

  <span class="keyword">private</span>:
      <span class="type">int</span> id_color <span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>;
      <span class="type">int</span> id_spread <span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>;
      <span class="type">int</span> id_size <span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>;
  };

  <span class="keyword">struct</span> LineVertex {
      <span class="type">float</span> x;
      <span class="type">float</span> y;
      <span class="type">float</span> t;
      <span class="keyword">inline</span> <span class="type">void</span> set(<span class="type">float</span> xx<span class="operator">,</span> <span class="type">float</span> yy<span class="operator">,</span> <span class="type">float</span> tt) { x <span class="operator">=</span> xx; y <span class="operator">=</span> yy; t <span class="operator">=</span> tt; }
  };

  <span class="keyword">static</span> <span class="keyword">const</span> <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>AttributeSet <span class="operator">&amp;</span>attributes()
  {
      <span class="keyword">static</span> <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>Attribute attr<span class="operator">[</span><span class="operator">]</span> <span class="operator">=</span> {
          <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>Attribute<span class="operator">::</span>create(<span class="number">0</span><span class="operator">,</span> <span class="number">2</span><span class="operator">,</span> GL_FLOAT<span class="operator">,</span> <span class="keyword">true</span>)<span class="operator">,</span>
          <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>Attribute<span class="operator">::</span>create(<span class="number">1</span><span class="operator">,</span> <span class="number">1</span><span class="operator">,</span> GL_FLOAT)
      };
      <span class="keyword">static</span> <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>AttributeSet set <span class="operator">=</span> { <span class="number">2</span><span class="operator">,</span> <span class="number">3</span> <span class="operator">*</span> <span class="keyword">sizeof</span>(<span class="type">float</span>)<span class="operator">,</span> attr };
      <span class="keyword">return</span> set;
  }

  LineNode<span class="operator">::</span>LineNode(<span class="type">float</span> size<span class="operator">,</span> <span class="type">float</span> spread<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtgui/qcolor.html">QColor</a></span> <span class="operator">&amp;</span>color)
      : m_geometry(attributes()<span class="operator">,</span> <span class="number">0</span>)
  {
      setGeometry(<span class="operator">&amp;</span>m_geometry);
      m_geometry<span class="operator">.</span>setDrawingMode(GL_TRIANGLE_STRIP);

      <span class="type"><a href="qsgsimplematerial.html">QSGSimpleMaterial</a></span><span class="operator">&lt;</span>LineMaterial<span class="operator">&gt;</span> <span class="operator">*</span>m <span class="operator">=</span> LineShader<span class="operator">::</span>createMaterial();
      m<span class="operator">-</span><span class="operator">&gt;</span>state()<span class="operator">-</span><span class="operator">&gt;</span>color <span class="operator">=</span> color;
      m<span class="operator">-</span><span class="operator">&gt;</span>state()<span class="operator">-</span><span class="operator">&gt;</span>size <span class="operator">=</span> size;
      m<span class="operator">-</span><span class="operator">&gt;</span>state()<span class="operator">-</span><span class="operator">&gt;</span>spread <span class="operator">=</span> spread;
      m<span class="operator">-</span><span class="operator">&gt;</span>setFlag(<span class="type"><a href="qsgmaterial.html">QSGMaterial</a></span><span class="operator">::</span>Blending);
      setMaterial(m);
      setFlag(OwnsMaterial);
  }

  <span class="comment">/*
   * Assumes that samples have values in the range of 0 to 1 and scales them to
   * the height of bounds. The samples are stretched out horizontally along the
   * width of the bounds.
   *
   * The position of each pair of points is identical, but we use the third value
   * &quot;t&quot; to shift the point up or down and to add antialiasing.
   */</span>
  <span class="type">void</span> LineNode<span class="operator">::</span>updateGeometry(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qrectf.html">QRectF</a></span> <span class="operator">&amp;</span>bounds<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="../qtcore/qlist.html">QList</a></span><span class="operator">&lt;</span><span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">&gt;</span> <span class="operator">&amp;</span>samples)
  {
      m_geometry<span class="operator">.</span>allocate(samples<span class="operator">.</span>size() <span class="operator">*</span> <span class="number">2</span>);

      <span class="type">float</span> x <span class="operator">=</span> bounds<span class="operator">.</span>x();
      <span class="type">float</span> y <span class="operator">=</span> bounds<span class="operator">.</span>y();
      <span class="type">float</span> w <span class="operator">=</span> bounds<span class="operator">.</span>width();
      <span class="type">float</span> h <span class="operator">=</span> bounds<span class="operator">.</span>height();

      <span class="type">float</span> dx <span class="operator">=</span> w <span class="operator">/</span> (samples<span class="operator">.</span>size() <span class="operator">-</span> <span class="number">1</span>);

      LineVertex <span class="operator">*</span>v <span class="operator">=</span> (LineVertex <span class="operator">*</span>) m_geometry<span class="operator">.</span>vertexData();
      <span class="keyword">for</span> (<span class="type">int</span> i<span class="operator">=</span><span class="number">0</span>; i<span class="operator">&lt;</span>samples<span class="operator">.</span>size(); <span class="operator">+</span><span class="operator">+</span>i) {
          v<span class="operator">[</span>i<span class="operator">*</span><span class="number">2</span><span class="operator">+</span><span class="number">0</span><span class="operator">]</span><span class="operator">.</span>set(x <span class="operator">+</span> dx <span class="operator">*</span> i<span class="operator">,</span> y <span class="operator">+</span> samples<span class="operator">.</span>at(i) <span class="operator">*</span> h<span class="operator">,</span> <span class="number">0</span>);
          v<span class="operator">[</span>i<span class="operator">*</span><span class="number">2</span><span class="operator">+</span><span class="number">1</span><span class="operator">]</span><span class="operator">.</span>set(x <span class="operator">+</span> dx <span class="operator">*</span> i<span class="operator">,</span> y <span class="operator">+</span> samples<span class="operator">.</span>at(i) <span class="operator">*</span> h<span class="operator">,</span> <span class="number">1</span>);
      }

      markDirty(<span class="type"><a href="qsgnode.html">QSGNode</a></span><span class="operator">::</span>DirtyGeometry);
  }

</pre>
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<!-- @@@scenegraph/graph/linenode.cpp -->
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